共聚物
环氧化物
马来酸酐
高分子化学
聚酯纤维
聚合
丙交酯
化学
材料科学
聚合物
有机化学
催化作用
作者
Yübo Wang,Ming‐Qian Wang,Yong Shi,Xiao‐Lu Chen,Dong‐Po Song,Yuesheng Li,Bin Wang
标识
DOI:10.1002/macp.202200079
摘要
Abstract Switchable copolymerization of oxygenated heterocycle mixtures by a single catalytic system has been proved to be a promising approach to sequence‐controlled block copolymers. However, there are still big challenges in one‐step synthesis of multiblock copolymers containing unsaturated polyester blocks from maleic anhydride, epoxides, and lactone mixtures. Herein, a switchable pathway for polylactide‐ b ‐poly(MAH‐ alt ‐epoxide)‐ b ‐polylactide block copolymers is established. The excellent chemoselectivity in multicomponent copolymerization is achieved by bipyridine bisphenolate aluminum complexes that can induce an obvious kinetic differentiation between ring‐opening copolymerization of maleic anhydride/epoxides and ring‐opening polymerization of lactide. The scope of the epoxide for switchable copolymerization is explored and it is found that the steric hindrance of the substituents on epoxide significantly influences the formation of block copolymers. Block copolymers with various sequential and topological structures can be easily prepared by exquisite selection of different initiators. Furthermore, it is demonstrated that the conversion of cis‐ maleate units in the block copolyester could be completely converted to trans ‐fumarate units by isomerization without chain degradation, cross‐linking, and chain scrambling.
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